Key



Patented Nov. 3, 1925.

UNITED STATES PATENT OFFICE...

CHARLES F. PRESTON, SR., 0F MAMARONECK, NEW YORK.

KEY.

Application filed January 11, 1924. Serial No. 685,646.

To all tU/lGlTL it may concern:

Be it known that I, CHARLES F. Pnns'ion, Sr., a citizen of the United States, and a resident of Mamaroneck, in the county of Vestchester and State of New York, have.

ing the shaft but usually means are provided for increasing the friction between the pulley and the shaft by strengthening the clamping means by which the pulleys are attached to the shaft. Normally such clamping means or set screws are suflicient to retain the pulleys in position and prevent slippage. During cold weather it requires increased power from the prime mover to set machinery in operation due to the fact that the machines are cold. In such cases the extra power exerted by the prime mover and transmitted through the pulleys results in the pulley loosening its grip onthe shaft. Once a pulley has lost its grip on the shaft it is very difficult to prevent it from slip ping. Consequently, when such an accidentoecurs it often necessitates shutting down of the machine shops and the like'for some considerable time until the pulley has been removed and means introduced for more rigidly attaching the pulley in position. The efiiciency of large machine shops is often seriously reduced in this way, causing the loss of large amounts of money. Sometimes pulleys are attached to the shafts by means of keys which engage in a slot in the pulley and a slot in the shaft. This method is not always satisfactory since it weakens the shaft. Pulleys mounted in this way will not stand a greater strain than what is required to shear off the key.

The general object of this invention is the provision of a cheap, simple and eificient key for attaching pulleys and the like to unslotted shafts.

This object is accomplished by providing a key, for mounting in key slots in pulleys and the like, consisting of a body having 5 sides which converge toward the working face, and gripping members formed .on the working face for engaging andembedding in the shaft.

This and other objects ofthe invention I willbe more clearly understood from the following detailed description and accompany 111g drawings.

Figure 1 is a perspective view of a split pulley attached to a shaft by means of the Figure 2 is a horizontal section alongthe line 22, Figure 1; Figure 3 is across section along the line 33, Figure 2, showing a cross section of the key; i i Figure 4 is a perspective view of the key; Figure 5 is a cross. section showing the key attaching anordinary unsplit pulley to v a shaft; y

Figure 6 shows a cross section of a'modi fied form of the key, illustrating how a shim might be used for projecting "the gripping members into engagement with the shaft;

Figure 7 is a longitudinal section along the line 7-7, Figure 6; i

,Figure 8 is another .modification of the device, disclosing three lines of. gripping members; i A a Figure 9 is an enlarged cross section, of the key. I p i Referring to the abovementioned drawings, the key consists of a .brodylO having sides 11 and l2converging toward the were ing face 13. Since the sides 11 and 12 converge toward the working face it follows that the outer facele is greater in width than the working face. As shown in Figure l, gripping members 15 and 16 are formed at the inner extremities of the converging sides or along the line at which'said converging sides intersect the. working face, The" working face between these gripping members would preferably be grooved so that the gripping members might the more easily embedthemselves in any-shaft with which they engage. In some cases, as shown in Figure 4, a plurality of notches 17 would be cut in each of the gripping members 15 llO 

